Retina Lock features a revolutionary intunnel vision systemin that extends your effective range Four StackTight .019in pins Light Trap Technology for low-light shooting PinPocket fiber-protective design 6061 aircraft-grade aluminum construction 3-axis adjustability Extends your effective range by 20 yards with Retina Lock. When you can see the full Green ring, you know youre in precisely the same release position, every time. The IQ Bowsight with Retina Lock 4-Pin Bow Sight features four StackTight .019in pins, Light Trap Technology for low-light shooting, PinPocket fiber-protective design, 6061 aircraft-grade aluminum construction, and 3-axis adjustability. Color: Gray.